Deuterium Retention in Tungsten with Different Grain Elongation Direction Irradiated by Plasma in APSEDAS

Deuterium retention after the low energy plasma irradiation was investigated using the polycrystalline tungsten samples of which grain elongation directions are parallel and perpendicular with respect to the surface. Fluence dependence of the retention measured by means of thermal desorption spectroscopy showed that it is 2-5 times larger for the sample with the perpendicular grain elongation. Thermal desorption of trapped deuterium has been modeled under the fast diffusion assumption with the defects trapping energy of about 2 eV. Possible mechanism of the deuterium retention and thermal desorption has been proposed.